The present invention relates to implantable medical devices, and more particularly to an implantable programmable pump having multiple reservoirs and a multiple lumen catheter through which independent medications may be delivered to a patient at programmed times or upon demand.
Patients typically require short bursts of independent medications delivered at unique times. Such medications, or drugs, may be delivered via independently accessed reservoirs or may be bolused on demand via a suitable controller. Patients experiencing pain, and receiving medication therefor, may require a short acting, independently-delivered, analgesic rather than an incremental bolus of an admixture or of morphine alone. Spasticity patients may require a burst of pain medications in addition to anti-spasticity medications, or another drug to temporarily increase tone during patient transfers, or other critical times. For example, a cocktail mixture of pain medication in conjunction with another drug that counteracts baclofen for a short period of time may also assist in patient transfers, or other critical times when the patient's muscles require increased tone.
U.S. Pat. No. 4,588,394 teaches a totally subcutaneously implantable infusion reservoir and pump system that includes a variable capacity reservoir for receiving and storing fluids containing medications for delivery to a catheter, which catheter directs the medications to a specific infusion location in the body. A pump and valving arrangement is interposed between the reservoir and the catheter to facilitate and control the transfer of the medications from the reservoir to the catheter in a safe and efficient manner. There is no provision for the delivery of multiple medications through the same catheter.
U.S. Pat. No. 4,449,983 discloses an osmotic device that delivers two beneficial drugs to an environment of use. The device comprises a wall surrounding a lumen divided into a first compartment containing a drug that is separated by a hydrogel partition from a second compartment containing a different drug. An orifice through the wall communicates with the first compartment for delivering drug formulation from the first compartment, and another orifice through the wall communicates with the second compartment for delivering drug formulation from the second compartment. In use, drug formulation is dispensed separately from each compartment by fluid being imbibed through the wall of the device into each compartment at a rate controlled by the permeability of the wall and the osmotic pressure gradient across the wall against the drug formulation in each compartment. A solution is thus produced in each compartment containing drugs. Through the expansion and swelling of the hydrogel, the drug formulation is dispensed through the respective orifices at a controlled and continuous rate over a prolonged period to time. There is no provision for bolus drug delivery over a short period of time, or for programmed rates of delivery.
U.S. Pat. No. 5,240,713 teaches a dual rate agent delivery device that provides for the controlled delivery of a beneficial agent in a hydrophilic carrier, followed by a continuous and sustained delivery of an agent in a controlled and uniform amount over a prolonged period of time. However, the dual rates are not programmable, but are rather controlled through the physical attributes of the device and osmotic pumping. The U.S. Pat. No. 5,240,713 further provides a comprehensive list of prior art relating to drug delivery devices.
What is needed is an implantable pump capable of independently delivering multiple medications at independently programmable rates.